1. Field of the Invention
The present invention relates to a barium sulfate imparting an excellent transparent feeling to the bare skin and effectively hiding the freckles and spots on the skin and to a cosmetic composition comprising the barium sulfate.
2. Description of the Background Art
Barium sulfate is widely used as a shading material for the x-ray photography, a .gamma.-ray absorber, a white pigment, and the like because of its characteristics unharmful to humans and its strong shielding capability. The applications of conventional barium sulfate to cosmetics, especially to foundation cosmetics, have been with some problems, such as its poor extendibility over the skin, inadequate adherence to the skin, insufficient transparency, and the inferior feeling to the bare skin which the conventional barium sulfate imparts after use.
In order to overcome these disadvantages of barium sulfate in the application to cosmetics, barium sulfate with a larger particle size (Japanese Patent Laid-open No. 41718/1983) and plate-like or needle-like barium sulfate crystals (Japanese Patent Laid-open (kokai) No. 174238/1987) have been proposed.
The production of such barium sulfate, however, involves complicated processes because of the requirement of a post-treatment of barium sulfate after synthesis, such as the treatment with heat or mineral acid. In addition, such a post-treatment develops the desired plate-like structure only insufficiently and the complete removal of crude barium sulfate after the post-treatment is difficult. There has been no barium sulfate which completely satisfied the requirements desired for the cosmetic material.
In view of this situation, the present inventors have undertaken extensive studies in order to develop barium sulfate satisfying the above-mentioned requirements. As a result, the inventors have found that barium sulfate (a) having a plate-like structure (defined more specifically below) and barium sulfate (A) having specific optical characteristics (defined more specifically below) exhibited excellent extendibility and adhesion to the skin, possessed high light-scattering and transparent characteristics, and could effectively hide the spots or freckles on the skin. These findings have led to the completion of the present invention.